Coherent massless particle beams such as lasers have been successful and spawned many disruptive technologies. A massive counterpart to lasers, namely coherent matterwave beams, may hold the promise of similar and even more revolutionary technologies. Generating massive coherent beams, however, has been elusive. A major obstacle in producing coherence in matterwaves is to change the phase of beam particles without modifying the energy of the particles. Conventional phase modifying effects may lead to a change in the energy, thus modifying the wavelength of the particles and making it difficult to synchronize the particles for coherence. While coherence for photons may be achieved through photon emission enhancement via resonance, a similar technique for massive particles (e.g., particles with mass) may not work because the velocity of the massive particles is a function of the wavelength. The speed of photons is the speed of light, regardless of the energy. This dependence of the energy on the speed of the particles may make it difficult for massive particles to become coherent unless a way is found for changing the massive particle phase without changing the energy.